im having a bit of a problem with the impeller in the external filter on my 180l, the pump is a Fluval 304 and what i assume to be the impeller is making a gawd awful noise! its so bad that it woke me up last night (and i sleep like a baby!). ive had a look at the impeller and compared it to a 104 (never been used) we bought for £5 for spares at that big fish show down at ‘hayland island’. i noitced that the impeller pieces kinda separated in my hand on the 304 whereas they were all in one piece on the 104. so ive decided im going to get a new impeller for it off ebay unless someone tells me there s a cheaper way? I’ve noticed there are 2 different types of impeller available to me and unfortunately im no fluid mechanic so i was hoping someone here might be, or at least know the answer to my question?

mines the curved bladed impeller so i think you’ve made it clear for me now. ive played around with the impeller and think its sounding alot better except for the resonating sound coming from it which (in a sherlock moment) i believe indicates the impeller and shaft need to be replaced, they are about 4-5 years old anyways. thanks for the help Dunc.

Diana Berberich has a noise Fluval 304, replaced all theparts in the impeller assembly and it still has a clatter. What’s the matter?

I have had similar problems with Marineland powerheads. Within a the warranty period, Marineland will send you anew rotor. If that doesn’t work, they will send, youguessed it, another rotor. If that doesn’t work, they willsend a new powerhead. Or so has been my experience.

These two-pole, permanent magnet rotor, AC motors areextraordinarily simple. In motors of this type, peopleoften say there is only one moving part, meaning themagnetic rotor, which spins within a “rotating”electromagnetic field generated by a pair of coils housedaround the rotor (usually sealed in epoxy or some otherpotting material). If the rotor is the only moving partand it ain’t rubbing, what else could possibly make theclatter? Well, probably the second moving part that theyall have.

The common culprit on Marineland powerheads is thewater-vane wheel, which is the small set of blades thatactually spin the water, forcing it through the powerheador pump. These wheels are not fixed to the rotor shaft butcan rotate freely about 225 degrees or about 3/4 of a turn. If these wheels are just a tad too loose, they will causethe pump or powerhead to clatter.

Old rotors can have wheels that have worn loose. This isone reason most powerhead manufacturers forbid using on/offcycling timers (so-called wave makers) on their powerheads;it promotes an early end of quiet life for the rotor wheel.

*But new rotors can have wheels that are too loose,*although the rate of occurrence seems to vary bymanufacturer. In my small experience, Marineland has ahigh probability and Eheim an extremely low one. (How manyMarinelanders say their Magnum is quiet vs how manyEheimers?)

Other factors that can cause a clatter: worn or poorlyfitting bearings or misaligned bearing seats. But I thinkthis is a rather rare reason for pump clatter. Bearingscan be replaced if they are at fault but seat alignment canbe harder or easier to deal with. It can be harder becausethe seat alignment is generally fixed by the manufacture ofthe pump housing. But it can be easier because, with some,a little push here, a little realignment pressure there andyou can help to quiet a noisy pump — but only if bearingseat alignment is the culprit in the first place.

If you’re having trouble even after replacing the impeller and shaft, have a browse through that ^.

Thanks again Dunc! i did notice when playing with the impeller again that one side of the plastic that surrounds the shaft was more worn on one side which makes perfect sense for the sound. guna buy both bits on ebay now.

If you buy the entire assembly i.e. impellor(Shaft and blade) you should cover yourselfIME rattling like that is usually caused by an impellor which has worn down and is no longerperfectly balanced usually blades. (That is when it doesn’t disintegrate in your hands when you first take it out)

So a new shaft on its own would make little difference(unless it is egg shaped) Try rolling it across a smooth surface to see how even it is